Chord organ switching circuit for selectively playing either chords or single notes by depressing one key



Dec. 19, 1967 J BRAND ET AL 3,359,358

CHORD ORGAN SWITCHING CIRCUIT FOR SELEGTIVEIJY PLAYING EITHER CHORDS OR SINGLE NOTES BY DEPRESSING CNE KEY Filed May- 22, 1963 2 Sheets-Sheet l LT W Q N T Bcw A ny f N Wm J5 mm mm nm @N N .mN

Dec. 19, 1967 J. R. ammo E L 3,359,358

CHORD ORGAN SWITCHING CIRCUIT FOR SELECTIVELY PLAYING EITHER CHORDS OR SINGLE NOTES BY DEPRESSING ONE KEY Filed May 22, 1963 2 Sheets-Sheet 2 JOHN R. Bxzmvo B+ STAVNLEY CUTLER INVENTORS ZJM ATToQNEv United States Patent 3 359,358 CHORD (BEGAN SWITCHING CIRCUIT FOR SELECTIVELY PLAYENG EITHER CHORDS 0R SINGLE NOTES BY DEPRESSING ()NE KEY This invention relates to electronic organ circuits and more particularly to circuits in which a chord, rather than a single note or octave, is sounded when any one of a certain group of keys is pressed.

It is an object of this invention to provide an improved chord organ circuit in which a plurality of tone signals may be applied to an output bus by the closing of a single-switch contact.

It is a further object of this invention to provide an improved chord organ circuit in which playing keys of the organ keyboard may be used either to play single notes in their proper relationship to the balance of the keyboard or complete musical chords.

It is a further object of this invention to provide a chord organ circuit in which a multi-note chord may be sounded, and in which one or more notes have odd and even harmonics and the remaining notes contain substantially odd harmonics only.

A further object of this invention is to provide an organ structure and electronic circuit such that a single key of the organ may be employed to play a single note, or alternately to play a combination of notes.

In accordance with these and other objects which will become apparent hereinafter, a preferred form of the present invention is disclose-d in the accompanying drawings wherein:

FIGURE 1 is a circuit diagram of the particular organ circuitry pertaining to this invention.

FIGURE 2 is a schematic of the embodiment.

FIGURE 3 is a schematic of an alternate embodiment.

In the electronic organ art, the tones are generated by devices which will be referred to herein as tone means. In the drawing, reference character 12 designates one of twelve tone means which together deliver all of the tones of the chromatic scale. Each tone means is capable of delivering several related tones, and the illustrated embodiment is adapted to deliver three octavely related tones. Each of the tone means, represented by reference character 12 has three output terminals 13, 14, and 16 at which appear octavely related tones of a given note. For the purpose of illustration, tone means 12 is assumed to be a generator for note C. Therefore, there appears at terminals 13, 14, and 16, respectively, the note C2; the first octave thereabove C3; and the second octave up, C4. The tone means 12 contains a master oscillator which generates the pitch of C4 and in turn drives an Eccles- Jordan type divider which generates C3. The latter, in turn, drives another Eccles-lordan divider which generates C2. The output wave form of both C3 and C2 (dividers) is essentially a rectangular wave which is intrinsically rich in odd-order harmonics and contains few or no even-order harmonics.

The tone means 12 is connected to a signal distribution network 17 having seven output terminals 18, 19, 21, 22, 23, 24, and 26. Network 17 includes a plurality of interconnected resistors that combine the outputs from terminals 13, 14, and 16 in various ways to deliver the unaltered wave form from the generator, and also deliver octavely related mixtures to produce signals including both odd and even harmonics. C2 is applied directly from the terminal 13 to the treminal 18. This same note C2 is also applied from the terminal 13 to the terminal 19 through a resistor 27. Also, applied to the output terminal 19, is a portion of the output of C3 from terminal 14, which in effect adds even-order harmonics to the signal from C2 appearing at terminal 19.

In similar fashion, combinations containing both even and odd-order harmonics appear at terminals 19, 21, 22 and 23.

Each of the output terminals of the distribution network 17 feeds to one wire of three multiple wire cables 37, 38, or 39, leading to a respective switch bank 41, 42, or 43. The switch bank 43, fed by the cable 39, consists of a row of single-pole double-throw switches which are connected to be operated by the respective keys of an upper keyboard on a two manual organ. Each switch of the bank has a connecting terminal to which the wire from cable 39 connects. Each switch arm or pole, for example pole 44, rests in a first operable position against a grounded contact in the form of bus 46, in the quiescent position, i.e., when the key of the keyboard is not in use. When the key is pressed, the switch arm pole 44 is raised to a second operable position into contact with an output bus 47 connected to an upper keyboard voice circuit.

The cable 38 feeds the lower keyboard bank of switches 42. These switches 42 are connected to be operated respectively by keys 45 forming the lower keyboard of the organ. The switch bank 42 is divide-d into two sections, a chord key switch section 48, and the remaining section 49.

In accordance with the present invention, switch section of the lower keyboard is designed to be operated either as an ordinary keyboard or as a chord keyboard at the will of the operator. When in chord operation, the third bank of switches 41, fed by the cable 37, is employed. When in non-chord operation, the bank 41 is isolated from the output circuit of the organ and plays no effective part in the operation.

The switch bank 41 comprises a plurality of singlepole, double-throw switches 51 each ganged to a corresponding switch 52 in the switch bank 42, both switches being operated by the key 45. Each switch 51 has a connecting terminal to receive connections from the feed cable 37. In quiescent position, i.e., with the key 45 at rest, the throw arm of switch 51 rests in a first operable position against a lower contact in the form of a busbar 53 which is grounded.

The upper contact against which the switch 51 may-engage is an upper busbar 57. Bus 57 leads to the pole of a double-throw switch 58. The switch 58 is manually accessible to the organist, and may either ground bus 57 by being thrown to its upper position, or it may be connected, by being thrown into its lower position, to an output line 59. Line leads to the lower keyboard voicing circuits. The output bus from the switch bank 42 also connects to the output line 59, and the other bus leads to ground.

It is to be understood that the organ includes the aforementioned voicing circuits, which in turn lead to suitable amplifiers, and thence to transducers in the form of loudspeakers, earphones, tone cabinets, and like output means.

To the terminal which is connected to the switch 51 of the switch bank 41, are connected two musically related tone signals, for example G2 and E2. These signals are brought from the output terminal of the G and E tone means respectively, corresponding to the terminal 18 of the C tone generator 12 shown. Tone generators have two terminals. Normally one of these terminals is grounded and the other is the output. If the output terminals of two tone generators are connected together, there will be such severe interaction that the signals are completely the chord keymixed and neither generator signal would be available independently. Hence, this invention employs isolating resistors 60 connected into the leads from the G and E generators, and the switch 51 is then kept at ground or connected to output depending upon the position of key 45. Thus, a signal coming from the generator G, for example, will reach the common terminal of the switch 51, and will follow the path of least resistance to the ground or output. It will not have a significant cross-talk eliect upon the generator of the tone E. Likewise, the tone generator E will have no significant effect upon the tone generator G.

The operation of the circuit is substantially as follows:

If the organist does not wish to employ the chord organ feature, switch 58 is placed in its ground position. This grounds the bus 57, so that even though the switch 51 is moved to its upper position every time the key 45 put line 59 from the switch bank 41. The only output appearing is that occasioned by the closing of the switch 52, which applies the single note played, for example C2, to the output line 59. As noted, this is a complex tone which contains a large measure of the signal C2, plus an attenuated portion of the octavely related signal C3. In this manner, the organ may be played as though the chord bank 41 did not exist.

If the organist wishes to employ the chord feature, he moves switch 58 to its lower position, thus connecting the upper bus 57 of the switch bank 41 to the output line 59. The keys 45 of the chord key switch section 48, in the lower keyboard, then become in eflect chord keys, with depression of a key sounding a three-note chord instead of only a single note. In some cases, the note played will correspond to the name of the chord which is sounded, although in other cases, this is not so. For example, when key 45, which plays note C2, is pressed, it operates both the arm of a switch 52 and the arm of a switch 51. The switch 52 applies the note C2 to the output line 59 from the cable 38. Through the cable 37 are conducted two tones, G2 and E2, thence through the resistors 60, to the output line 59, and through the switch 58. There is thus sounded a C-major chord, with the C2 being predominent by virtue of its even and odd order harmonics. The G2 and E2, on the other hand, contain only odd order harmonics.

It will be noted that by grouping non-octavely musically related tone signals, for example, G2 and E2, and connecting them both fixedly to a signal terminal, i.e. the switch 51, in the chord switch bank 41, it is possible to sound these related tones, i.e. G2 and E2, by closing only a single contact; that is, by closing only the switch 51 to the output bus 57. This makes possible a minimization in the number of individual switches required for chord organ operation, with the consequent saving in initial and maintenance costs.

In FIGURE 2, the circuitry of FIGURE 1 is illustrated schematically. Generators 70 and 71 operate through resistances 72 and 73 respectively, and are joined at a common terminal 74 of a switch having a pole 75.

A third generator 76 operates through the pole of switch 77. Switches 75 and 77 are operated in a gang by a common organ key.

The output of the organ is represented by the signal line and speaker symbol indicated by the reference character 78. The generator 76 operates through the switch 77 directly to the output 78 of the organ. However, the output of generator 70 and 71, in addition to passing through the switch pole 75, must pass through the switch having a pole 79. This switch is manually accessible to the operator and is opened whenever only a single note from generator 76 is desired. It is closed when a chord is desired.

Alternatively, as shown in FIGURE 3, generators 80 and 81 are connected to a common terminal 84 of a switch having a pole 85.

is played, there is no output applied to the out- Generator 86 operates through a switch having a pole 87. However, rather than leading to a speaker output system, these switches having poles 85 and 87 are in a common gang operated by the key of the organ to connect a source of power to the generators 89, $1 and 86. An output, including a speaker, indicated by reference character 88, is permanently connected to the output of the generators. A manual selecting switch 89 determines whether the generators and 81 will be employed with the generator 86 in the production of a chord.

Thus, it will be seen that in FIGURE 2, the generators are in constant operation, and the switches determine which of the outputs will be employed to produce the audible signal. On the other hand, as in FIGURE 3, the switches determine which of the generators will be energized to product the audible signal.

It will also be seen that in an electronic musical instrument having a plurality of tone means for generating signals corresponding to notes of a musical scale, and in which instrument there is a key of a keyboard for expressing tones from the tone means, the invention comprises the combination of a circuit means including only one single-pole switch connecting a tone generator and a non-octavely related tone generator together, to the output circuit of the system. This invention thereby permits operation by a single-pole switch to unite two musically related notes into a system whereby they may be employed as a combined output note with or without another note to produce a chord.

While the instant invention has been shown and described herein in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention which is therefore not to be limited to the details disclosed herein, but is to be afforded the full scope of the following claims.

What is claimed is:

1. In an electronic musical instrument having a plurality of tone means for generating signals corresponding to notes in a musical scale, and a keyboard for expressing tones from said tone means, the combination of;

a single pole switch means having a plurality of terminals and operable by a key of the keyboard;

impedance means connecting a first of said tone means to a first terminal of said switch means and connecting at least another non-octavely related tone means to said first terminal;

said switch means having a pole operable between a first station interconnecting said first terminal and a second terminal, and a second station interconnecting said first terminal with a third terminal, said second terminal connected to ground, and a circuit means for connecting the third terminal to the output of the electronic musical instrument, operation of any said key causing its corresponding switch means to swing said pole from said first station at ground to said second station connected to said out- P whereby there is applied to said output a plurality of tone signals.

2. In an electronic musical instrument having a plurality of tone means for generating signals corresponding to notes in a musical scale, and a keyboard for expressing tones from said tone means, the combination of;

a single pole first switch means having a plurality of terminals and operable by a key of the keyboard; impedance means connecting a first of said tone means to a first terminal of said first switch means and connecting at least another non-octavely related tone means to said first terminal;

said first switch means having a pole operable between a first station interconnecting said first terminal and a second terminal, and a second station interconnecting said first terminal with a third terminal, said second terminal connected to ground, and circuit means for connecting the third terminal to the output of the electronic musical instrument, operation of any said key causing its corresponding said first switch means to swing said pole from said first station at ground to said second station connected to said output; a second switch means first switch means; and

means connecting a third tone means to the first ter minal of said second switch means and connecting the second terminal of said second switch means to said output of the musical instrument, pressing of said key causing its corresponding gang of switches to connect to said output of the musical instrument;

whereby, there is applied to said output musically related tone forming a chord.

3. In an electronic musical instrument having a plurality of tone means for generating signals corresponding to notes in a musical scale, the output wave form of said tone means being comprised substantially of a fundamental and odd harmonics thereof, and a keyboard for expressing tones from said tone means, the combination of:

a single pole switch having a first terminal with a pole,

a second terminal connected to ground, and a third terminal; impedance means connecting a first of said tone means to said first terminal of said switch, and connecting at least another non-octavely related tone means to said first terminal, said pole of the switch operable between said second terminal and said third terminal;

circuit means for connecting said third terminal of said switch to the output of the electronic musical instrument;

operable in gang with the a second single pole switch having a first terminal with a pole, a second terminal connected to ground, and a third terminal;

means connecting still another non-octavely related tone means to the first terminal of said second switch and connecting a portion of the output of the octave higher tone means to said first terminal;

circuit means for connecting said third terminal of said second switch to the output of the electronic musical instrument;

a mechanical gang apparatus providing interconnection of a key of said keyboard with said first and second switch, pressing said key thereby causing both switches to move from the ground positions to the output of the musical instrument;

whereby, there is applied to said output a plurality of tone signals.

4. In the musical instrument defined in claim 3, said tone means being related so as to produce a musical chord.

References Cited UNITED STATES PATENTS 2,250,522 7/1941 Bonilla 241.29 2,964,986 12/1960 Johnson 841.29 3,098,888 7/1963 Tomcik 841.25 3,099,700 7/1963 Bergman 841.24 3,198,055 8/1965 Von Gunten 84-1.17

ARTHUR GAUSS, Primary Examiner. J. BUSCH, R. H. PLOTKIN, Assistant Examiners. 

1. IN AN ELECTRONIC MUSICAL INSTRUMENT HAVING A PLURALITY OF TONE MEANS FOR GENERATING SIGNALS CORRESPONDING TO NOTES IN A MUSICAL SCALE, AND A KEYBOARD FOR EXPRESSING TONES FROM SAID TONE MEANS, THE COMBINATION OF; A SINGLE POLE SWITCH MEANS HAVING A PLURALITY OF TERMINALS AND OPERABLE BY A KEY OF THE KEYBOARD; IMPEDANCE MEANS CONNECTING A FIRST OF SAID TONE MEANS TO A FIRST TERMINAL OF SAID SWITCH MEANS AND CONNECTING AT LEAST ANOTHER NON-OCTAVELY RELATED TONE MEANS TO SAID FIRST TERMINAL; SAID SWITCH MEANS HAVING A POLE OPERABLE BETWEEN A FIRST STATION INTERCONNECTING SAID FIRST TERMINAL AND A SECOND TERMINAL, AND A SECOND STATION INTERCONNECTING SAID FIRST TERMINAL WITH A THIRD TERMINAL, SAID SECOND TERMINAL CONNECTED TO GROUND, AND A CIRCUIT MEANS FOR CONNECTING THE THIRD TERMINAL TO THE OUTPUT OF THE ELECTRONIC MUSICAL INSTRUMENT, OPERATION OF ANY SAID KEY CAUSING ITS CORRESPONDING SWITCH MEANS TO SWING SAID POLE FROM SAID FIRST STATION AT GROUND TO SAID SECOND STATION CONNECTED TO SAID OUTPUT; WHEREBY THERE IS APPLIED TO SAID OUTPUT A PLURALITY OF TONE SIGNALS. 